1. Field of the Invention
The present invention relates to a dynamic balancing guide system and, in particular, a press dynamic balancer guide system in which rotation of a balancer weight around the axis of reciprocation is prevented.
2. Description of the Related Art
Mechanical presses such as straight side presses and gap frame presses for stamping and drawing comprise a frame for reciprocal motion towards and away from the bed. The slide is driven by a crankshaft having a connecting arm connected to the slide to which is mounted the upper die. The lower die is mounted to a bolster which, in turn, is connected to the bed. Such mechanical presses are widely used for blanking and drawing operations and varying substantially the size and available tonnage depending on their use.
The primary source of stored mechanical energy in a mechanical press is a flywheel. The flywheel is located between the main drive and the clutch. The flywheel and the flywheel bearings are mounted on either the driveshaft, crankshaft, or the press frame by use of a quill. The main motor replenishes the energy lost from the drive wheel during press stamping operations when the clutch couples the flywheel to the press driven parts. During engagement of the clutch, the flywheel drops in speed and the press drive parts come up to press running speeds. During engagement with the clutch, the press wheel rotates in unison with the clutch while the flywheel bearings have no relative motion, except in the case of the use of the quill where relative motion is always present.
During press operation, the slide reciprocates up and down creating inertial forces on the press components. Balancer weights have been used to dynamically balance these inertial forces. Typically, the balancer weights have been guided either by guide posts or balancer guides.
One problem with the prior art is that the difference in thermal expansion of the balancer weight and the press frame limits the effectiveness of the current guide system. The balancer weight, because of its large mass, does not heat up or cool down at the same rate as the press frame where part of the balancer guide system is mounted. The different thermal expansion of the balancer weight as compared to the press frame causes the running clearance to be reduced or eliminated altogether in the current type of guide systems. If the clearance between the balancer weight and balancer guide system is too small, the guide system may seize and/or cause high wear resulting in a very short life of the guide system.
One current solution to reduce the effects of thermal expansion is to provide additional running clearance in the guide system which allows for thermal expansion. A drawback to this solution is that this added clearance, if too large, results in greater axial and rotational movement of the balancer weight about the longitudinal axis or reciprocation causing more vibration to be added to the press. This vibration may then be translated into the press ram or slide causing unwanted ram movement thus, affecting part quality. In addition, high wear may occur on the balancer guide system as a result of high vibration caused by too much clearance.
Therefore, the goal of this present invention is to produce a dynamic balancer guide system which assures proper running clearance to prevent thermal close-out while ensuring that the clearance is not too great causing high vibration and wear.